Technical Abstract:
Nitrogen (N) application generally results in increased nitrous oxide (N2O) emissions from cropland. Commercially available controlled-release N fertilizers were evaluated for their potential to reduce N2O emissions from a clay loam soil compared to conventionally used granular urea and urea-ammonium nitrate (UAN) fertilizers in an irrigated no-till (NT) corn (Zea mays L.) production system. Controlled-release N fertilizers evaluated were: a polymer-coated urea (ESN), stabilized urea (SuperU), and UAN+AgrotainPlus (contains nitrification and urease inhibitors). Each N source was surface band applied (202 kg N ha-1) near the corn row at emergence and watered into the soil the next day. A subsurface band ESN treatment (ESNssb) was included. Nitrous oxide fluxes were measured during two growing seasons and after harvest using static, vented chambers. All N sources had significantly lower growing season N2O emissions than granular urea (0.7% of applied N), with UAN+AgrotainPlus (0.2% of applied N) and ESN (0.3% of applied N) having lower emissions than UAN (0.4% of applied N). Similar trends were observed when expressing N2O emissions on a grain yield and N uptake basis. Corn grain yields were not different among N sources, but greater than the check with no N applied. Selection of N fertilizer source can be a mitigation practice for reducing N2O emissions in NT, irrigated corn in semi-arid areas.